As well as being a kinase associated with age-dependent penetrant forms of Parkinsons disease, Leucine-rich repeat kinase 2 (LRRK2) is also an authentic GTP binding protein. There are mutations in the GTP-binding ROC (Ras of complex proteins) domain and the adjacent COR (C-terminal of ROC) in LRRK2 that cause Parkinsons disease. The aim of this project is to understand why LRRK2 and related homologue LRRK1 bind GTP and what effect this has on the protein. Our ongoing work aims to identify proteins that bind to the ROC:COR domains of LRRK2, ie the GTP-binding region. We predict that understanding what these proteins are will give insight into the function of LRRK2 and may help understand mutations within those domains. We are currently pursuing interactions of LRRK2 with chaperones and co-chaperones, as well as novel interactors, in this region. At this point, we have mapped a series of interactions around the COR domain of LRRK2 that suggest that there is a multivalent protein complex. Ongoing work in the laboratory is aimed at understanding the functional impact of these interactions in cellular models.